Extron electronic IPL T CR48 manual Communication and Control, Ports Overview, Relay ports

Communication and Control

Ports Overview

Contact closure input ports

The contact closure inputs on the IPL T CR48 are able to detect a closed circuit between any of the inputs and ground. The contact closure input ports utilize a 1 kohm pull-up resistor in a TTL (5VDC) circuit to sense external switch or contact closure.

By connecting one side of an external switch or relay to the contact closure ground port and the other side to one of the four contact closure input ports, logic 1 (closed) can be produced. Logic 0 (open) can be produced by disconnecting either side of the external switch or relay from the IPL T CR48.

+5V

1K

Figure 4-1 — Equivalent circuit for control closure input

Relay ports

The relay ports can be used for remote switching of low level signals. The relays can be activated via software in three ways, through

1.the Port Settings default Web page found under the Configuration tab (see figure 4-5)

2.Telnet

3.an event script running on the IPL T CR48

The Port Settings Web page allows the user to turn any of the eight relays “on” or “off.”

Telnet allows the user to send SIS commands (Refer to the “Command/response table” later in this chapter) to turn the relays “on” or “off” directly.

Event scripting allows an event script to turn the relays “on” or “off” based on the state of the four inputs on the IPL T CR48, or any other event script conditions.

States of the relay ports are volatile; if a given relay port is “on” and the unit’s power is turned off, the state of the port is not remembered. When the unit is powered on, the relay ports are open and the corresponding LED will be “off.”

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